WowAce

When a mob casts a spell at a player the center icon displays that spell at the highest priority even though the center icon is not set to show such a thing. This is annoying on a pack with a lot of casters casting on a target with a dispelable debuff as it hides the fact there is a dispelable debuff.

Here are my center icon settings:

I dont understand what you mean when you say "the center icon displays that spell", what caster spell ? In your screenshot there are no banzai status linked (the one that displays casted spells).  Are you speaking about Raid Debuffs ? Then please specify which instance and raid debuff you are speaking about.

Tested (assuming we are speaking about raid debufs), and all is working fine, dispelleable debuffs icons are displayed first.

This happens with all casted spells in all BFA dungeons. I do not believe I am talking about raid debuffs as the icons appear when a spell is being cast on a target and there is no debuff for that spell. The fact that i have no banzai status linked is what is confusing me about why the casted spells are being shown.

What is happening has no sense, enable lua errors to check if some error is happening.

You could try to  unlink all statuses linked to icon center, then remove and recreate icon center indicator.

I disabled all my other addons and could not reproduce this so it must be a conflict, sorry for wasting your time.